Pull-up and dip exercises provide excellent conditioning because each exercise develops several major muscle groups in the upper body. Conventional pull-up and dip exercise devices require a great deal of upper body strength because both exercises require the user to support and move the entire body against the effects of gravity. Often, the person exercising cannot perform multiple repetitions of these exercises. Even if multiple repetitions can be accomplished, the exerciser tires quickly and cannot usually maintain a high number of repetitions over multiple sets. Users of exercise equipment recognize that performing multiple repetitions over a number of sets produces more beneficial muscular development than performing a small number of repetitions over fewer sets. A device to assist the user to perform multiple repetitions of these exercises would provide a better exercise and increased health benefits to the user.
Prior pull-up and dip exercise devices have attempted to address the problem of assisting the user to perform a greater number of repetitions of these exercises. However, while these prior devices provide assistance, they tend to restrict the ability of the user to perform the exercise in a natural pull-up or dip position. These prior devices have also tended to be complicated, difficult to operate and expensive to manufacture.
Towley's device, U.S. Pat. No. 5,011,139 utilizes a foot bar mechanism for providing the user with assistance. Towley teaches a device with a frame, both pull-up and dip extension bars and a pivotal foot bar connected by a pulley system to a set of weights. To gain the assistance, the user stands on the foot bar while performing the desired exercise.
Potts, U.S. Pat. No. 4,846,458, discloses a frame similar to Towley, but the assisting portion of the Potts invention consists of a pneumatically powered, computer controlled platform upon which the user stands while exercising. A complicated computer control panel regulates the air compression motor which provides the air compression to the pneumatic ram which moves against a pivotal beam attached to the platform. This somewhat complex system used to provide the assisting force includes a power source, two separate relays, a compressor, an accumulator with a bleed valve, an electronic console, and a pneumatic ram having a safety valve and a flow control valve.
Roberts, U.S. Pat. No. 4,111,414, discloses a pull-up assisting device incorporating a single pulley and weight stack system attached to a harness for cancelling at least a portion of the weight of the user during the exercise. The Roberts device only teaches this method of assistance for pull-up exercises, not dips. Roberts teaches assisting the user by sitting in the harness when performing the exercise. The device incorporates an assistance system wherein the pulley cable transfers a counter-balancing force from the weight stack to a harness looped around the user's legs. The system is less manageable than the previously discussed devices because the user must first set the weight, then pull down the harness, and finally step into the harness while the cable remains in tension.
Therefore, a need has arisen in the industry for an improved device to assist the user to perform pull-up and dip exercises simply and in a more natural body position.